Optical transceivers have become an ubiquitous link in the fiber optic data communication and telecommunication industries for transferring information between host computer devices and fiber optic networks. Typically, each transceiver module includes a transmitter optical subassembly (TOSA) and a receiver optical subassembly (ROSA), along with the circuitry for the control thereof. The TOSA converts electrical signals from the host device into optical signals for launching into an optical fiber. Conversely, the ROSA receives optical signals from an optical fiber and converts them to electrical signals for transmission to the host device. A front end of the transceiver module includes optical connector ports for receiving connectorized ends of optical fibers, while a rear end of the transceiver module includes an electrical connector for insertion into a mating electrical connector on a circuit board in the host device.
With the advent of “hot pluggable” optical transceivers, latching devices have become a popular safety feature to ensure that the transceiver module is held within a guide rail or cage until purposely removed. Bail latching devices have become particularly popular, due to their functional and ergonomic advantages. Previous bail designs are disclosed in U.S. Pat. No. 5,901,263 issued to IBM Corp., and U.S. Pat. No. 6,439,918 issued to Finisar Corp. The bail in the IBM device forces plastic arms, which are normally biased inwardly, outwardly into engagement with the guide rail system. The bail in the Finisar device pivots a separate pivoting latch member, which is normally biased into engagement with the cage by a specially designed extension of the housing.
Recent designs for cages, in particular (see FIGS. 1) a cage 1 designed for an XFP module 2 (according to the XFP Multi-Source Agreement), includes spring fingers 3 (one of which is shown), which are biased inwardly into the cage 1 for engaging a shoulder 4 on the transceiver housing 6. During insertion through a bezel 7 and the open end of the cage 1, the spring fingers 3 slide along a rear end of the transceiver housing 6 until the spring fingers 3 slide over the a shoulder 4 into engagement with abutment surfaces 8, which prevents the module 2 from being removed. At the same time an electrical connector 5 on the transceiver module 2 engages an electrical connector 10 in the cage 1, thereby electrically connecting the transceiver module 2 to a host board 9. The XFP transceiver module 2 also includes a heat sink 11 mounted on the module 2 by a spring clip 12.
An object of the present invention is to overcome the shortcomings of the prior art by providing an unlatching mechanism for disengaging a cage mounted spring finger from an abutment surface on a transceiver housing.